Study results have demonstrated that extremely serious long-term corollaries of diabetes mellitus (for example blinding of the patient due to retinopathy) can be prevented by continuous in vivo monitoring of the time profile of the glucose concentration. This allows the dosage of the medication required (insulin) to be adjusted exactly at any point in time and thus the blood sugar levels to be kept within narrow limits at all times like in a healthy person. A method of this type and a suitable device are described in U.S. Pat. No. 5,507,288, for example. The patent describes in particular the continuous monitoring of the glucose concentration in the body of a patient, which is of crucial medical significance.
In order for the medication process to be as efficient as possible it is desired to be able to determine not only a current value of the concentration of an analyte, but also predict future concentration values. The prediction of future values of the concentration of an analyte is of particular significance in the case of diabetes, not only to counteract an increase of the blood glucose concentration beyond a critical value by administering insulin, but also to alert the patient to a decrease of the blood glucose concentration.
The prediction of a future concentration of an analyte value in the living body of a human or animal is made significantly more complicated by the fact that concentration values depend not only on historic values, but also on other parameters, such as food and medication intake or physical exercise.
A method for monitoring the blood glucose concentration is known from U.S. Pat. No. 6,272,480 B1, in which an artificial neuronal network is used to derive a prediction of future blood glucose values from a time series of glucose concentrations that were measured. However, a significant disadvantage of artificial neuronal networks is that they need to be trained prior to their use and yield unreliable results when confronted with time series data outside of their training range.
From EP 1102194 A2, a method is known in which blood glucose concentration values measured at consecutive points in time are extrapolated taking into consideration patient-specific data, such as, in particular, any carbohydrate intake and insulin administration. For practical applications, the need to account for such patient-specific data is a major disadvantage, since accounting for such data is difficult and often error-prone.